Add shader constant support for Vulkan

engine/gfx/public/gfx.hpp

@@ -144,13 +144,13 @@ struct GFXShaderBinding {
 
 struct GFXShaderConstant {
     int index = 0;
-    
+
     enum class Type {
         Integer
-    } type;
+    } type = Type::Integer;
     
     union {
-        int value;
+        int value = 0;
     };
 };
 

engine/gfx/vulkan/src/gfx_vulkan.cpp

@@ -774,7 +774,29 @@ GFXPipeline* GFXVulkan::create_graphics_pipeline(const GFXGraphicsPipelineCreate
 
 	std::vector<VkPipelineShaderStageCreateInfo> shaderStages;
 
-	if (has_vertex_stage) {
+    VkSpecializationInfo vertex_specialization_info;
+    std::vector<VkSpecializationMapEntry> vertex_map_entries;
+
+    VkSpecializationInfo fragment_specialization_info;
+    std::vector<VkSpecializationMapEntry> fragment_map_entries;
+
+   const auto fill_map_entries = [](const GFXShaderConstants& constants, std::vector<VkSpecializationMapEntry>& entries) {
+       for(int i = 0; i < constants.size(); i++) {
+          // TODO: we only support int specializations (which is okay right now)
+          VkSpecializationMapEntry entry = {};
+          entry.constantID = constants[i].index;
+          entry.size = sizeof(int);
+          entry.offset = sizeof(int) * i;
+
+          entries.push_back(entry);
+       }
+   };
+
+
+   std::vector<int> vertex_data;
+   std::vector<int> fragment_data;
+
+   if (has_vertex_stage) {
 		const bool vertex_use_shader_source = !info.shaders.vertex_src.is_path();
 
 		if (vertex_use_shader_source) {
@@ -797,9 +819,24 @@ GFXPipeline* GFXVulkan::create_graphics_pipeline(const GFXGraphicsPipelineCreate
 		vertShaderStageInfo.stage = VK_SHADER_STAGE_VERTEX_BIT;
 		vertShaderStageInfo.module = vertex_module;
 		vertShaderStageInfo.pName = "main";
+        
+        if(!info.shaders.vertex_constants.empty()) {
+           fill_map_entries(info.shaders.vertex_constants, vertex_map_entries);
+           vertex_specialization_info.mapEntryCount = vertex_map_entries.size();
+           vertex_specialization_info.pMapEntries = vertex_map_entries.data();
+
+           for(auto constant : info.shaders.vertex_constants) {
+              vertex_data.push_back(constant.value);
+           }
+
+           vertex_specialization_info.dataSize = vertex_data.size() * sizeof(int);
+           vertex_specialization_info.pData = vertex_data.data();
+
+           vertShaderStageInfo.pSpecializationInfo = &vertex_specialization_info;
+        }
 
 		shaderStages.push_back(vertShaderStageInfo);
-	}
+    }
 
 	if (has_fragment_stage) {
         const bool fragment_use_shader_source = !info.shaders.fragment_src.is_path();
@@ -824,6 +861,21 @@ GFXPipeline* GFXVulkan::create_graphics_pipeline(const GFXGraphicsPipelineCreate
 		fragShaderStageInfo.stage = VK_SHADER_STAGE_FRAGMENT_BIT;
 		fragShaderStageInfo.module = fragment_module;
 		fragShaderStageInfo.pName = "main";
+        
+        if(!info.shaders.fragment_constants.empty()) {
+           fill_map_entries(info.shaders.fragment_constants, fragment_map_entries);
+           fragment_specialization_info.mapEntryCount = fragment_map_entries.size();
+           fragment_specialization_info.pMapEntries = fragment_map_entries.data();
+
+           for(auto constant : info.shaders.fragment_constants) {
+              fragment_data.push_back(constant.value);
+           }
+
+           fragment_specialization_info.dataSize = fragment_data.size() * sizeof(int);
+           fragment_specialization_info.pData = fragment_data.data();
+
+           fragShaderStageInfo.pSpecializationInfo = &fragment_specialization_info;
+        }
 
 		shaderStages.push_back(fragShaderStageInfo);
 	}
@@ -1373,6 +1425,7 @@ void GFXVulkan::submit(GFXCommandBuffer* command_buffer, const platform::window_
 		{
             VkBuffer buffer = ((GFXVulkanBuffer*)command.data.set_vertex_buffer.buffer)->handle;
 			VkDeviceSize offset = command.data.set_vertex_buffer.offset;
+                        
 			vkCmdBindVertexBuffers(cmd, command.data.set_vertex_buffer.index, 1, &buffer, &offset);
 		}
 			break;
@@ -1381,7 +1434,7 @@ void GFXVulkan::submit(GFXCommandBuffer* command_buffer, const platform::window_
 			VkIndexType indexType = VK_INDEX_TYPE_UINT32;
 			if (command.data.set_index_buffer.index_type == IndexType::UINT16)
 				indexType = VK_INDEX_TYPE_UINT16;
-
+            
             vkCmdBindIndexBuffer(cmd, ((GFXVulkanBuffer*)command.data.set_index_buffer.buffer)->handle, 0, indexType);
 		}
 			break;
@@ -1390,7 +1443,7 @@ void GFXVulkan::submit(GFXCommandBuffer* command_buffer, const platform::window_
 		    VkShaderStageFlags applicableStages = VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT;
 		    if(is_compute)
 		        applicableStages = VK_SHADER_STAGE_COMPUTE_BIT;
-
+            
 			if(currentPipeline != nullptr)
 				vkCmdPushConstants(cmd, currentPipeline->layout, applicableStages , 0, command.data.set_push_constant.size, command.data.set_push_constant.bytes.data());
 		}
@@ -1401,7 +1454,7 @@ void GFXVulkan::submit(GFXCommandBuffer* command_buffer, const platform::window_
 			bsb.buffer = command.data.bind_shader_buffer.buffer;
 			bsb.offset = command.data.bind_shader_buffer.offset;
 			bsb.size = command.data.bind_shader_buffer.size;
-
+            
 			boundShaderBuffers[command.data.bind_shader_buffer.index] = bsb;
 		}
 			break;
@@ -1425,8 +1478,9 @@ void GFXVulkan::submit(GFXCommandBuffer* command_buffer, const platform::window_
 			break;
 		case GFXCommandType::DrawIndexed:
 		{
-			if(try_bind_descriptor())
+            if(try_bind_descriptor()) {
 				vkCmdDrawIndexed(cmd, command.data.draw_indexed.index_count, 1, command.data.draw_indexed.first_index, command.data.draw_indexed.vertex_offset, 0);
+            }
 		}
 		break;
 		case GFXCommandType::SetDepthBias: